i have a gti i did the apr tune with the apr intake and a highflow cat down pipe altogether around the power levels are around hp and tq this is really as high as you wan na go before having to do internal engine and transmission modifications the apr transmission tcu tune is also something to look at it makes the tranny work better with the added power look up deutsche auto on youtube they show tons of mods available on the mk gti look into oil catch can upgraded diverter valve turbo muffler delete lowering springs steel oil pan obd device and vent boost gauge